Fluoxetine is a selective inhibitor of serotonin reuptake used to treat several psychiatric disorders and it has also been described as a substance used to commit suicide or that is associated with accidental intoxications; therefore fluoxetine is linked with clinical and forensic cases. Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) is a dipteran of medical and forensic interest. To study the effect of fluoxetine on the development of C. vicina, an acute lethal dose was administered to porcine muscle (model 1) and Sus scrofa L. pigs (model 2). The duration of each stage of development, the length and the grosso modo external morphology of the specimens were recorded. Detection and quantification of the antidepressant was performed by gas chromatography coupled with mass spectrometry (GC-MS). The results obtained were the same regardless of the model used. There were no differences in the duration of developmental stages between fluoxetine treatment and control groups. The size and external morphology of the specimens did not show changes due to treatment with the drug. In conclusion, fluoxetine had no detectable effect on the development of C. vicina, and hence the estimation of postmortem interval (PMI) would not be compromised if the drug is detected in cases in which it could have been the cause of death or have been involved in circumstances associated with it.